1. Field of the Invention
This invention relates to a method for producing baseballs and softballs, specifically a production process for baseballs and softballs and the ball covers thereof.
2. Description of Related Art
Presently, the main structure of formal baseballs and softballs for competition consists mainly of an elastic spherical core part being wrapped in an outer leather cover. Because of the material of the leather covers and the higher labor costs, the production rate is low and there is a lack of uniformity in the balls, and therefore polyurethane (PU) material has conveniently been used for the ball covers. Concerning this PU material used for the ball covers, and the current production method for producing the ball covers of the softballs or baseballs, the current method generally requires an independently formed spherical core being placed in the mold cavity of two attaching semicircular molds, or this spherical core is placed in the mold cavity of two corresponding figure of 8 shaped ball cover molds which join to form the mold cavity of the mold, and then PU material is injected into the ball cover mold cavity to cover the spherical core placed in the mold, and finally the molds are removed to reveal the complete ball.
This production method still has some flaws in the production process. After PU material is injected through the inlet grooves on the ball cover mold to the spherical core placed in the cavity of the ball cover mold, the PU material covers the spherical core, and when heated foam is formed. Air outlets are set on both sides of the inlet grooves which connect to the inside of the mold, but as these outlets are only situated at the top, when the mold is heated and the foam is produced, the gas possibly can't all be released out the air outlets, and this small amount of gas which can't be expelled forms air bubbles in the PU in the mold, and these bubbles left in the outside cover result in uneven integrity and thickness of the outside covers, and thus result in flaws in the outside covers.
The outside cover is formed by injecting liquid PU material onto the spherical core, and because this spherical core is made from either PU, rubber or cork, the surface of this spherical core doesn't have a strong bond, and doesn't attach strongly to the foam formed in the PU, resulting in a loose attachment between the spherical core and ball cover, which results in a shortened lifespan and the ball easily changing shape.
Therefore, how to solve the above problems is an issue demanding a prompt solution by industry.